Tolerance to Zn Deficiency and P-Zn Interaction in Wheat Seedlings Cultured in Chelator-buffered Solutions

Zinc efficiency means the ability of crop to grow and yield well in Zn deficient soil. Wheat genotypes differ greatly in the adaptation to Zn-deficient soil conditions. Therefore, selecting and breeding Zn-efficient genotypes has been recognized as the most logical approach for solving the problem of Zn deficiency in plants and humans. Now, the improvement of Zn efficiency in wheat has become a major task for plant breeders in many countries.

Zinc deficiency is common in crops that are grown in areas with high level of available soil P. High level of available soil P can also reduce the bioavailability of Zn to humans by increasing the phytic acid content in cereal grain. For these reasons, understanding the relationship between P and Zn is an important component of effective agronomy practices to apply P fertilizer.

For these reasons, researchers conducted two experiments using chelator-buffered nutrient solutions to characterize the differences in tolerance to Zn deficiency among three winter wheat (Triticum aestivum L.) genotypes (Mianyang19, Han6172, Xinmai13) and to investigate the relationship between P and Zn nutrition in wheat species. In their experiments, four indices, Zn efficiency, relative shoot-to-root ratio, total Zn uptake in shoot, and shoot dry weight were used to compare the tolerance to Zn deficiency among three wheat genotypes.

The results indicated that the four indices could be used in breeding selection for Zn uptake-efficient genotypes. The genotype Han6172 was the most tolerant to Zn deficient, followed by Mianyang19, and then Xinmai13. Specifically, Han6172 had the highest Zn uptake efficiency among the three genotypes. The addition of P to the growth medium increased Zn uptake and translocation from roots to shoots. Total Zn content of the wheat plant was 43% higher with 0.6 mmol/L P treatment than that of control with 0 mmol /L P treatment. The Zn translocation ratios from roots to shoots were increased by 16% and 26% with 0.6 mmol/L P treatment and 3 mmol/L P treatment, respectively, compared with 0 mmol/L P treatment. In contrast, high Zn concentrations in the growth medium inhibited P translocation from roots to shoots, but the inhibitive effects were not strong. Sixty-six percent of P taken up by wheat plants was translocated to the wheat shoots at 0 μmol/L Zn treatment, while the percent was 60% at 3 μmol/L Zn treatment.

The related work has been published on Journal of Arid Land (2011, 3(3): 206-213.). It can be link from: http://jal.xjegi.com/EN/abstract/abstract93.shtml#.

Indices of experiment 1 characterized the tolerance to Zn deficiency of different wheat genotypes. (a) Zn efficiency; (b) shoo/root ratio at 0.5 μmol/L Zn treatment; (c) total plant Zn content at 0.5 μmol/L Zn treatment; and (d) shoot dry weight at 0.5 μmol/L Zn treatment. Data represent means ± SD (n = 4)